Radio communication systems are known in the art. Recently, communications systems that each accommodate a variety of communications services have been developed. For example, U.S. Ser. No. 08/131,535 entitled "Method And Apparatus For Supporting At Least Two Communication Services In A Communication System", filed on Oct. 1, 1993 by Krebs, et al. discloses a communication system that will support both telephone services and dispatch services. Dispatch services and telephone services differ in a variety of ways from one another, and certain problems can be encountered when providing common infrastructure to support both services. For example, regardless of which service is requested, sufficient communication resources may not exist to immediately support the request. When this occurs in a dispatch context, a dispatch system will typically automatically notify the dispatch user of subsequent availability of the resource. Contrary to this, the telephone user will not be subsequently advised of resource availability. As a result, it can be seen that different users of a system can have different expectations as to how that system will respond to their requests for service.
In order to notify dispatch users that a previously denied communication request can now be accommodated, the system infrastructure will typically maintain a request queue. In this way, with or without the use of additional degrees of prioritization, previously denied service requests can be met. Therefore, although dispatch users are typically confronted with a 5 to 20 percent probability of unavailability of service at the time of initially requesting dispatch service, the dispatch user also typically expects to be notified of service availability within a few seconds to a few minutes.
Since telephone users are typically not subsequently notified of resource availability once their initial request has been denied, the infrastructure that accommodates their communications processing does not maintain a request queue. In the ordinary situation, this does not provide a problem. When, however, both services share a common infrastructure and a common set of resources, a variety of problems can result. In particular, during particularly busy request conditions, the dispatch users may receive an undue amount of system resources with respect to telephone users, since the dispatch users are queued, and hence have a considerable advantage over their unqueued counterparts.
Accordingly, a need exists to better accommodate the need for telephone subscriber units in a multi-service shared infrastructure communications environment to obtain requested communications resources.